diff --git a/src/tests/encore/basic/functionCast.enc b/src/tests/encore/basic/functionCast.enc
new file mode 100644
index 000000000..3cf2acef0
--- /dev/null
+++ b/src/tests/encore/basic/functionCast.enc
@@ -0,0 +1,11 @@
+def fun() : (String, String) {
+  ("Hello", "world")
+}
+
+class Main {
+  def main() : void {
+    let foo = fun : () -> (String, String);
+    match foo() with
+      (h, w) => print("{} {}\n", h, w)
+  }
+}
diff --git a/src/tests/encore/basic/functionCast.out b/src/tests/encore/basic/functionCast.out
new file mode 100644
index 000000000..802992c42
--- /dev/null
+++ b/src/tests/encore/basic/functionCast.out
@@ -0,0 +1 @@
+Hello world
diff --git a/src/types/Types.hs b/src/types/Types.hs
index 3edca3fb8..4ecb3ef13 100644
--- a/src/types/Types.hs
+++ b/src/types/Types.hs
@@ -375,7 +375,7 @@ typeMapM f ty@CapabilityType{capability} = do
   f ty{capability = capability'}
 typeMapM f ty@ArrowType{argTypes, resultType} = do
   argTypes' <- mapM (typeMapM f) argTypes
-  resultType' <- f resultType
+  resultType' <- typeMapM f resultType
   f ty{argTypes = argTypes'
       ,resultType = resultType'}
 typeMapM f ty@TupleType{argTypes} = do